They’ve never stepped on the field for the University of Oklahoma. But they could be key performers for the Sooners this season.

OU has several talented redshirt and true freshmen at various positions and plenty of opportunity to earn playing time as fall camp opens. Receiver, cornerback and center are just a few positions that could be boosted by quick development from a freshman.

Early enrollee Trey Metoyer is an example of a freshman who developed quickly and will be counted on to make plays immediately.

Here are five freshmen looking to mirror Metoyer’s terrific spring while in the spotlight as preseason practice begins:

Teammates have raved about Shepard during summer workouts. A terrific athlete and consistent playmaker, he appears poised to make an impact at receiver and possibly on special teams. He’s been preparing himself for this moment for over a year, evidenced by his hard work in the weight room during his final years at Oklahoma City, Okla./Heritage Hall in preparation for college football.

Even though all signs point to the 2012 UnderArmour All-American being an impact player, you never know about true freshman until they do it with the lights on. How will he react when he’s put on his back after running a route across the middle? How quickly will he adjust to physical college cornerbacks? Fall camp will start to provide answers to those questions.

Simon is an elite talent with the physical ability to step right in and make a major impact on OU’s defense. A two-sport star in high school, Simon earned player of the year honors in basketball after signing with the Sooners in February. At 6-foot-1, 180 pounds, Simon brings terrific size and athleticism to the cornerback spot. And his high school coach, Antonio Knox, raves about Simon’s ball skills.

The Sooners could use a strong camp from Simon as they continue to try to shore up the cornerback position. Demontre Hurst is a rock at one cornerback spot and Aaron Colvin is moving to the other cornerback spot. Behind that duo? Things are wide open. It’s up to Simon to seize the opportunity.

At 6-foot-6, 318 pounds, Phillips is a beast. And he moves like a much smaller man. Returning All-Big 12 guard Gabe Ikard called him "the next Gerald McCoy." High praise, indeed. It’s hard to imagine Jordan Phillips never having an impact on the program. It’s just a matter of when.

The Sooners would like his emergence to begin this August. OU is solid in the defensive interior with three veteran, game-tested defensive tackles but the Sooners could use a defensive tackle to consistently causes havoc in the middle. If he’s had a strong and focused summer, Phillips could earn a spot in the rotation and potentially become a difference maker in the interior for OU.

Shannon made a great impression on new linebackers coach Tim Kish during the spring. He could provide quality depth at linebacker, similar to Corey Nelson’s role in the past two seasons and play a role on special teams. He has terrific instincts and a great feel for the position.

The Sooners will keep an eye on Shannon’s progress because OU needs young, up-and-coming performers at the position with seniors manning three of the the four linebacker positions on the two-deep depth chart.

With the loss of Ben Habern, Darlington could play this season. Habern said he wouldn’t be surprised if Darlington played during Big 12 Media Days and it turns out, the Sooners might really need the freshman to perform well in August. He’s underweight but he was generally regarded as the most ready to play of the offensive linemen signed by OU in February thanks to his intelligence and fundamentals.

Ikard will start at center but Nila Kasitati, who played center at times during the spring, is dealing with a heart issue and Austin Woods has been battling lymphoma. That makes OU’s depth at the position start to look dangerously thin. So the Sooners would love to see Darlington bring a physical presence to the table during his first set of practices as a Sooner.